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1.
T. G. Nikiforova 《Russian Journal of Electrochemistry》2010,46(12):1378-1382
Reduction of palladium(II) glycinate complexes in strongly acid 0.5 M NaClO4 solutions (pH 0.6 and 1.0) with variable palladium(II) complex and free glycine concentration was studied by the taking of
cyclic voltammograms at palladium rotating disc electrode. It is shown that it was a chelate monoglycinate palladium(II) complex
that was present in all studied solutions and underwent the reduction. The diffusion coefficient of the chelate monoglycinate
palladium(II) complex D = (6.5 ± 0.5) × 10−6 cm2/s was determined from the limiting diffusion current of the complex reduction. The monoglycinate palladium(II) complex reduction
occurred in the double-layer segment of the palladium charging curve; it was not complicated by hydrogen adsorption at electrodes.
The palladium(II) complex reduction half-wave potential was determined (E
1/2 = ∼0.300 to 0.330 V (SCE)). It is shown that the decreasing of the number of ligands coordinated by palladium via nitrogen
atom facilitates the complex reduction process. In particular, the reduction potentials of palladium(II) complexes with different
ligand number at palladium electrode shifted markedly toward negative potentials in the series: Pdgly+ < Pd(gly)2 < Pd(gly)42−. 相似文献
2.
A. G. Belobaba A. I. Maslii A. Zh. Medvedev 《Russian Journal of Applied Chemistry》2010,83(11):1952-1956
Palladium recovery from [Pd(NH3)4]Cl2 solutions (concentration in terms of the metal ∼1 g l−1) with flow-through porous electrodes was studied. The conditions of effective electrochemical recovery of Pd were found.
Various porous cathodes were compared. 相似文献
3.
Toshiyuki Fujii Souichirou Egusa Akihiro Uehara Akira Kirishima Isao Yamagishi Yasuji Morita Hajimu Yamana 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(2):475-478
Palladium complexation in concentrated nitric acid solutions was studied by UV/Vis absorption spectrophotometry. The ionic
strength of the solutions was fixed to I = 1, 3, or 5 mol dm−3 (M) by mixing of HNO3 and HClO4. The major palladium species were found to be Pd2+, PdNO3
+, and Pd(NO3)2. The formation constant of PdNO3
+ was determined to be β
1 = 1.32 (I = 1 M), 1.49 (I = 3 M), or 1.47 (I = 5 M), while that of Pd(NO3)2 to be β
2 = 0.45 (I = 3 M) or 0.14 (I = 5 M). 相似文献
4.
Nucleophilic substitution of Pd(RaaiR′)Cl2 [(RaaiR′ = 1-alkyl-2-(arylazo)imidazole, p-R-C6H4-N=N-C3H2NN-1-R′; where R = H(a)/ Me(b)/ Cl(c) and R′ = Et(1)/Bz(2)] with 2-Mercaptopyridine (2-SH-Py) in acetonitrile (MeCN) at 298 K, to form [Pd2(2-S-Py)4], has been studied spectrophotometrically under pseudo-first-order conditions and the analyses support the nucleophilic association
path. The reaction follows the rate law, Rate = {k
0 + k [2-SH-Py]
0
2
}[Pd(RaaiR′)Cl2]: first order in Pd(RaaiR′)Cl2 and second order in 2-SH-Py. The rate of the reaction follows the order: Pd(RaaiEt)Cl2
(1) < Pd(RaaiBz)Cl2
(2) and Pd(MeaaiR′)Cl2 (b) < Pd(HaaiR′)Cl2 (a) < Pd(ClaaiR′)Cl2 (c). External addition of Cl− (LiCl) and HCl suppresses the rate (Rate ∝ 1/[Cl−]0 & ∝1/[HCl]0). The reactions have been studied at different temperatures (293–308 K) and activation parameters (Δ‡ H° and Δ ‡ S°) of the reactions were calculated from the Eyring plot and support the proposed mechanism. 相似文献
5.
S. Dutta P. K. Mohapatra V. K. Manchanda A. K. Das 《Journal of Radioanalytical and Nuclear Chemistry》2007,274(2):245-250
The work describes a procedure of preconcentration and separation of trace amounts of Pd(II) by solid phase extraction of
the metal ion by dithiooxamide groups incorporated into a matrix of polystyrene-divinylbenzene whereas the determination of
palladium has been carried out by radiotracer technique using 109Pd (T
1/2 = 13.43 hr, E
γ = 311, 647 keV). The experiments were carried out using both batch method and column operation. Parameters such as the amount
of resin, effect of pH, equilibration rate, sorption and desorption of metal ions have been studied. The maximum sorption
capacity for palladium was found to be 0.10 mmol·g−1 at pH 6.0. The method is rapid, has a good accuracy and can be used routinely. 相似文献
6.
Prasanta Kumar Santra Ramkrishna Roy Chittaranjan Sinha 《Journal of Chemical Sciences》2000,112(5):523-534
2-(Arylazo)pyrimidines (aapm) are N,N′-chelating ligands and synthesise orange-red complexes of composition [Pd(aapm)Cl2],1, with Pd(MeCN)2Cl2 in MeCN. The complex hascis-PdCl2 configuration [v(Pd-Cl): 340, 360 cm−1]. The treatment of Tollen’s reagent (‘AgOH’) leads to chelatative hydroxylation in the pendant aryl ring, affording a green
phenolato complex, Pd(aapmO)Cl,5 (aapmO is deprotonated 2-((8-hydroxo)arylazo)pyrimidine). The reaction is also carried out by controlled addition of dilute
sodium hydroxide in air or by the addition of PhIO/m-chloroperbenzoic acid to a MeCN suspension of the complex. A single Pd-Cl stretch at 360 cm−1 supports the composition of phenolato complex. Unlike Pd(aapm)Cl2 the hydroxylated product, Pd(aapmO)Cl, has a structured intense absorption in the visible region near 670 nm. The Pd-Cl bond
in Pd(aapmO)Cl is highly sensitive to nucleophilic substitution and slowly hydrolyses in aqueous medium.
For Parts I and II, see references 16 and 17; for Part III,Synth. React. Inorg. Met.- Org. Chem. (in press) 相似文献
7.
The non-isothermal decomposition process of the powder sample of palladium acetylacetonate [Pd(acac)2] was investigated by thermogravimetric (TG) and the X-ray diffraction (XRD) techniques. Model-free isoconversional method
of Tang, applied to the investigated decomposition process, yield practically constant apparent activation energy in the range
of 0.05≤α≤0.95. It was established, that the Coats-Redfern (CR) method gives several statistically equivalent reaction models,
but only for the phase-boundary reaction models (R2 and R3), the calculated value of the apparent activation energy (E) is nearest to the values of E obtained by the Tang’s and Kissinger’s methods.
The apparent activation energy value obtained by the IKP method (132.4 kJ mol−1) displays a good agreement with the value of E obtained using the model-free analysis (130.3 kJ mol−1). The artificial isokinetic relationship (aIKR) was used for the numerical reconstruction of the experimental integral model
function, g(α). It was established that the numerically reconstructed experimental function follows R3 reaction model in the range of
α, taken from model-free analysis. Generally, decomposition process of Pd(acac)2 starts with initial nucleation which was characterized by rapid onset of an acceleratory reaction without presence of induction
period. 相似文献
8.
O. V. Belousov R. V. Borisov S. M. Zharkov A. S. Samoilo 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(1):35-40
The size-dependent effects of the heterogeneous reaction PdCl42− + 2e = Pd0 + 4Cl− were studied in hydrochloric acid solutions of H2PdCl4 at 40–70°C. Changes in the structural characteristics of palladium black were analyzed by transmission electron microscopy
and X-ray diffraction. The temperature dependence of the redox potential of the PdCl42−/Pd0 pair was used to determine the thermodynamic characteristics of aggregation of fine-dispersed palladium. The heat effect
of the reaction was in satisfactory agreement with direct differential scanning calorimetry measurements. 相似文献
9.
Carolina V. Barra Fillipe V. Rocha Adelino V. G. Netto B. Shimura Regina C. G. Frem Antonio E. Mauro Iracilda Z. Carlos Sandra R. Ananias Marcela B. Quilles 《Journal of Thermal Analysis and Calorimetry》2011,106(2):483-488
The pyrazole ligand 3,5-dimethyl-4-iodopyrazole (HdmIPz) has been used to obtain a series of palladium(II) complexes (1–4) of the type [PdX2(HdmIPz)2] {X = Cl− (1); Br− (2); I− (3); SCN− (4)}. All compounds have been isolated, purified, and characterized by means of elemental analysis, IR spectroscopy, 1H and 13C{1H}-NMR experiments, differential thermal analysis (DTA), and thermogravimetry (TG). The TG/DTA curves showed that the compounds
released ligands in the temperature range 137–605 °C, yielding metallic palladium as final residue. The complexes and the
ligand together with cisplatin have been tested in vitro by MTT assay for their cytotoxicity against two murine cancer cell
lines: mammary adenocarcinoma (LM3) and lung adenocarcinoma (LP07). 相似文献
10.
Electrochemistry of hydrofullerene C60H36 was studied by cyclic voltammetry in THF and CH2Cl2 in the −47–14 °C temperature range. Hydrofullerene undergoes reversible one-electron reduction to form a radical anion in
THF (E
0=−3.18 V (Fc0/Fc+), Fc=ferrocene) and irreversible one-electron oxidation in CH2Cl2 (E
p
a
=1.22 V (Fc0/Fc+)). The reduction potential was used to estimate electron affinity of hydrofullerene as EA=−0.33 eV. It was suggested that
C60H36 is an isomer withT-symmetry in which 12 double bonds form four isolated benzenoid rings located in vertices of an imaginary inscribed tetrahedron
on the molecular surface. For hydrofullerene, the “electrochemical gap” is an analog of the energy gap (HOMO−LUMO), equal
to (E
Ox−E
Red)=4.4 V, and indicates that C60H36 is a sufficiently “hard” molecule with a low reactivity in redox reactions.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2083–2087, November, 1999. 相似文献
11.
Pradip Kumar Ghosh Harasit Kumar Mandal Ambikesh Mahapatra 《Transition Metal Chemistry》2010,35(6):679-687
Interaction of adenine (A) with dichloro-[1-alkyl-2-(α-naphthylazo)imidazole] palladium(II) [Pd(α-NaiR)Cl2], 1 and dichloro-[1-alkyl-2-(β-naphthylazo)imidazole] palladium(II) [Pd(β-NaiR)Cl2], 2 {where R=Me (a), Et (b) or Bz (c)} in MeCN-water (50% v/v) medium to yield [{1-alkyl-2-(α-naphthylazo)imidazole}(adenine)]palladium(II) perchlorates (3a, 3b, 3c) and [{1-alkyl-2-(β-naphthylazo)imidazole}(adenine)]palladium(II) perchlorates (4a, 4b, 4c) was studied. The products were characterized by physico-chemical and spectroscopic methods. The reaction kinetics were second
order overall, being first order in both the Pd(II) complex and adenine. The effect of adding chloride was consistent with
rate-limiting dissociation of chloride from the complex. Thermodynamic parameters were determined from temperature variation
experiments. The second-order rate constant k
2
corroborates with the experimental Δ‡H° values, while the negative values of Δ‡S° indicate that the reaction proceeds through an associative inner sphere mechanism. 相似文献
12.
The determination of palladium in a road dust sample taken close to the highway (w
Pd=450 ng g−1) was carried out by the ICP-MS method after sample decomposition by aqua-regia. Analyses were evaluated by two methods: external calibration accompanied with mathematical correction of spectral interferences (EC) and isotope dilution measurement after separation of Pd by extraction to dibutyl sulfide solution (ID). In both cases, the uncertainties and accuracy of results were investigated. Although in the case of ideally homogeneous sample the repeatability of EC results (11 ng g−1 Pd) was somewhat lower than those of ID results (16 ng g−1 Pd), the uncertainties of results of both techniques were almost the same and they reached the level of 19 ng g−1 Pd. The main uncertainty source of the EC method is represented by the correction of spectral interferences. In case of real non-homogeneous sample, the main uncertainty component represents the soil sampling. The uncertainty of results (approx. 75 ng g−1 Pd) only slightly exceeded the repeatability (approx. 70 ng g−1 Pd). The accuracy of results was proven by analyses of CRM TDB–1 Diabas Rock (in case of ID) and by the standard addition method (in case of EC). 相似文献
13.
S. Lokhande S. A. Parab 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(13):2346-2349
Determination of ion-exchange equilibrium constant (K) for Cl−/I− and Cl−/C2O42− system was studied at different temperatures from 25 to 45°C and by varying concentration of iodide and oxalate ion solution.
For both uni-univalent and uni-bivalent exchange systems, using 0.5 g of ion-exchange resin DUOLITE A-116 (in chloride form),
the value of K increases with rise in temperature i.e., from 13.0 at 25°C to 19.05 at 45°C for Cl−/I− system and 33.0 at 25°C to 63.0 at 45°C for Cl−/C2O42− system indicating the endothermic ion-exchange reaction. The difference in K values at the same temperature for the two was related to the ionic charge of exchangeable ions in the solution. 相似文献
14.
Tahra Ayed Nathalie Guihéry Bahoueddine Tangour Jean-Claude Barthelat 《Theoretical chemistry accounts》2006,116(4-5):497-504
Correlated ab initio calculations have been performed on three dipalladium(I) complexes. These compounds differ both by the metal–metal interaction and by the metal–ligand interaction. The [Pd2Cl2(μ −H2PCH2PH2)2] complex exhibits a σ overlap between the two binding metallic orbitals and has no bridging ligand. In [Pd2Cl4(μ −CO)2]2−, the leading interaction between the two palladium involves a π overlap between the metallic orbitals and goes through the two bridging CO ligands. In [Pd2Cl2(μ −CO)(μ −H2PCH2 PH2)2], a single CO ligand bridges the two palladium atoms which interact through a hybrid σ–δ overlap. The three compounds also differ by the metal–metal distances. Surprisingly enough, while the palladium atoms are formally d
9 in all these complexes, none of them is paramagnetic. We propose here a detailed analysis of the electronic structures of these compounds and rationalize their chemical structures as well as the role of back-donation in the CO bridged compounds. Finally, since highly correlated treatments are used to describe these complexes, a detailed study of the role of both non-dynamical and dynamical correlations is performed. Concerning the [Pd2Cl4(μ −CO)2]2− complex, this analysis has revealed that the complex is not bound at the lowest correlated levels of calculation and therefore dynamical correlation is alone responsible for its binding energy. 相似文献
15.
Radiation-chemical transformations of chloride solutions in the presence of iodide additives were studied by pulse radiolysis.
Radical anion Cl2
⋅− oxidize I− ion, while in the secondary reactions Cl2 reacts with I− to form a mixed trihalide ion ICl2
−. A reaction model that satisfactorily describes the experimental data was proposed.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1336–1340, June, 2005. 相似文献
16.
Sahra C. Lemos Silmar J. S. Franchi Adelino V. G. Netto Antonio E. Mauro Oswaldo Treu-Filho Regina C. G. Frem Eduardo Tonon de Almeida Cláudia Torres 《Journal of Thermal Analysis and Calorimetry》2011,106(2):391-397
This work describes the synthesis, characterization, and the thermal behavior investigation of four palladium(II) complexes
with general formulae [PdX2(mba)2], in which mba = N-methylbenzylamine and X = OAc− (1), Cl− (2), Br− (3) or I− (4). The complexes were characterized by elemental analysis, infrared vibrational spectroscopy, and 1H nuclear magnetic resonance. The stoichiometry of the complexes was established by means of elemental analysis and thermogravimetry
(TG). TG/DTA curves showed that the thermodecomposition of the four complexes occurred in 3–4 steps, leading to metallic palladium
as final residue. The palladium content found in all curves was in agreement with the mass percentages calculated for the
complexes. The following thermal stability sequence was found: 3 > 2 > 4 > 1. The geometry optimization of 1, 2, 3, and 4, calculated using the DFT/B3LYP method, yielded a slightly distorted square planar environment around the Pd(II) ion made
by two anionic groups and two nitrogen atoms from the mba ligand (N1 and N2), in a trans-relationship. 相似文献
17.
Background
The anticancer properties of cisplatin and palladium(II) complexes stem from the ability of the cis-MCl2 fragment to bind to DNA bases. However, cisplatin also interacts with non-cancer cells, mainly through bonding molecules containing -SH groups, resulting in nephrotoxicity. This has aroused interest in the design of palladium(II) complexes of improved activity and lower toxicity. The reaction of DNA bases with palladium(II) complexes with chelating N,N/donors of the cis-MCl2 configuration constitutes a model system that may help explore the mechanism of cisplatin's anticancer activity. Heterocyclic compounds are found widely in nature and are essential to many biochemical processes. Amongst these naturally occurring compounds, the most thoroughly studied is that of pyrimidine. This was one of the factors that encouraged this study into the kinetics and mechanism of the interaction of 2-aminopyrimidine (2-NH2-Pym) with dichloro-{1-alkyl-2-(α-naphthylazo)imidazole}palladium(II) [Pd(α-NaiR)Cl2, 1] and dichloro-{1-alkyl-2-(β-naphthylazo)imidazole}palladium(II) [Pd(β-NaiR)Cl2, 2] complexes where the alkyl R = Me (a), Et (b), or Bz (c). 相似文献18.
G. Duplâtre L. M. Al-Shukri A. Haessler 《Journal of Radioanalytical and Nuclear Chemistry》1980,55(2):199-211
The rate constants for the reactions of positronium with halogen molecules and with halide ions in methanol (I2, Br2, Cl−, Br−) and in dimethylsulphoxide (I2, Cl−) have been measured. The variations of the ortho-positronium lifetime in mixtures of these solutes have been used for quantitative
determination of the formation constants of the corresponding polyhalides. These were found to be 2.9 and 5.4 M−1, respectively, for I2Cl− and I2Br− in methanol and 2.0 M−1 for I2Cl− in dimethylsulphoxide. Experiments on acidified AgClO4 solutions confirmed the formation, at molar concentrations, of the Ag2 ClO
4
+
species, very probably a triplet ion association. 相似文献
19.
The stability constants, β1, of the monochloride complex of Sm(III) have been determined in mixed system of methanol and water at 1.00 mol dm−3 ionic strength using a solvent extraction technique. The values of β1 increase with an increase in the mole fraction of methanol (X
s
) in the mixed solvent system when 0≤X
s
≤0.351. The interionic distance of Sm3+−Cl− (d
Sm−Cl) in the mixed solvent system was estimated by applying the Gibb's free energy derived from β1 to a Born-type equation. It was determined that an inflection point of the variation in the estimatedd
Sm−Cl againstX
s
was present in the vicinity ofX
s
=0.054. The inflection point ofd
Sm−Cl shows a value ofX
s
between those ofd
Eu−Cl andd
Nd−Cl previously obtained by us. 相似文献
20.
R. S. Lokhande P. U. Singare M. H. Dole 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(13):2313-2317
The study on thermodynamics of ion exchange equilibrium for uni-univalent Cl−/I−, Cl−/Br−, and uni-divalent Cl−/SO42−, Cl−/C2O42− reaction systems was carried out using ion-exchange resin Duolite A-113. The equilibrium constant K was calculated by taking into account the activity coefficient of ions both in solution as well as in the resin phase. The
K values calculated for uni-univalent and uni-divalent anion exchange reaction systems were observed to increase with rise
in temperature, indicating the endothermic exchange reactions having enthalpy values of 17.21, 36.60, 19.50, 18.43 kJ/mol
respectively. 相似文献